The present invention relates to a non-metallic vehicle air intake manifold and, more particularly, to an intake manifold which provides a fuel rail cavity for receiving a metallic fuel rail which is enclosed by a molded fuel rail cavity cover.
An air intake manifold distributes air to a vehicle engine""s cylinders. The manifold is located on the engine in the engine compartment of a vehicle. The intake manifold primarily includes a plurality of runners which communicate and distribute air to the engine cylinders. The runners are of a particular geometry to assure proper air flow thereto. One of the major factors that influences engine performance as determined by the air intake manifold, is the air flow runner length and their sectional area. Recently, non-metallic materials are used in the manufacture of air intake manifolds.
Recently, attempts have been made to mold a metallic fuel rail into the non-metallic intake manifold to minimize permeation of fuel therefrom. Overmolding a metallic fuel rail into the intake manifold may be relatively difficult, as the molding tool must interface against a relatively imprecise and thin walled fuel rail. Due to the imprecise interface, gaps or series of gaps may result between the molding tool and the fuel rail. Molded openings for a plurality of injector cups which interface with the fuel rail must also be maintained during the molding process which may likewise result in the formation of gaps. During the molding process, these gaps may fill with flash. The flash may potentially sever injector O-rings during installation, may inhibit injector installation, and may later detach and clog the fuel system.
Accordingly, it is desirable to provide a non-metallic air intake manifold having a metallic fuel rail and a method of manufacture therefor without the aforementioned assembly difficulties.
The intake manifold according to the present invention provides a fuel rail cavity which receives a metallic fuel rail which is enclosed by a molded fuel rail cavity cover.
The fuel rail is manufactured of a metallic material through a hydroforming, stamping, casting, semi-solid forming or other metal forming process. By separately locating the metallic fuel rail within the fuel rail cavity, alignment of fuel rail injector openings with each module cylinders and injector cup is readily facilitated.
The fuel rail communicates with each of a plurality of engine cylinders through a fuel module. A fuel module carrier assembly having module carriers is mounted between a lower manifold portion and the vehicle engine. The module carriers are cylindrical members that fit into corresponding module cylinders which extend from the lower manifold portion. An injector cup fits upon each module cylinder to provide an interface between the fuel module and the fuel rail.
Another intake manifold includes a fuel rail that directly interfaces with each fuel module through a bellows attached directly thereto. Each bellows is manufactured of a metallic material and attached directly to the fuel module and the fuel rail without the requirement of a resilient seal.
The present invention therefore provides a non-metallic air intake manifold having a metallic fuel rail and a method of manufacture therefor without the aforementioned assembly difficulties.